lobo improved

[maxbiri]

Hi Amtech2005
Yes the net capacitors is for decoupling all ic, same decoupling capacitors i designed near IC and other are in the net for better readable.
Even for power nets i used net alias.
There are 2 or 4 decoupling capacitor that must be deleted because i incorporate lm393 and 392 in a single lm339.
Yesterday i start design pcb but looking at schematic and pcb i was thinking about same others improvements.

1) I remember that 7660 dont have a simmetrical negative output and it give a lot of noise, so maybe i will redesign the power supply stage.

2) May be we can drive the oscillator stage at battery power and not 8 v, iìm not sure but is possible we gain 1-2cm in detection range.

Yes LS are obsolete an difficult to find i plan use TL072 oe lf 353 but any hint about other ic are wellcome!

Bye Max

[amtech2005]

lobo improoved

Maxbiri , the older the metal detector the harder it is to find a decent photo !!! Remember the "Original Lobo" was 20 khz. The new Lobo ST is around 17.5 khz......You can see the difference in the switches and the potetiometer to the left ...This should help a little....take care....Eugene

[amtech2005]

Lobo improoved

Hello again , Maxbiri. I looked at the last pdf schematic you posted again . Two things I noticed , 1. What is the capacitor network of "8 Caps" doing in the upper left of the schematic ? Are they for all the I.C.s ?? and 2. Did you complete all the power supply voltage connection's ? I will look at your schematic again tonight. This is a Great detector and I will try to find some close-up photo's of the original Lobo but it won't be easy !!!.....Good work you have done so far !!!! Also a week ago or so I read from another member's post about the LS204 chip , Are they almost obsolete/discontinued ??...Does the LS204 have a lot of noise ?? Maybe you should search for a better replacment ?? ...........Thanks..........Eugene

[maxbiri]

THere isn't any hint or critique abuot schematic i posted?
If so i will start design pcb, the more time consuming part in a pcb.
I'm looking for a photo of front panel, lobo classic not supertrack!
I need better understand the function of all swichs.

Bye Maxbiri

[amtech2005]

lobo improoved

Excellent Work !!! You know that you picked a "Great Detector" to work on !! I read the field test's on this detector and it was designed for small Gold nugget's but with the right search coil , the Lobo also work's excellent to find Old-Coins very "Deep" . Thank-You ...........Eugene

[maxbiri]

Here is a revision

Because i dont like lm392, it will cause proplems in pcb layout, I change lm 393 and comparator of lm 392 with a lm339.
Ok now i have a unused comparator.
I change lm392's operational with half lm358 and again have a unused operational.
With this change i hope have a better pcb layout whitout tracks goining from one side to other side of pcb.
I know that leave input of unused operational floating is not a good idea, what is better? connect all input and output to ground?

Thanks in advant

Bye Max

[maxbiri]

Hi all

Here are two pdf design i do starting from L.W. schematic, i try same little improvements, at least i think do.
What do you think?
There are others improvements that i can incorpotare in schematic?

Best regards
Maxbiri